Autoclave Process
Why are more Masons and Architects choosing Autoclave Block?
More resistant to water damage
- Autoclave’s drying and curing results in a tougher, stronger block less effected and more impermeable to moisture.
Consistency in Colour
- Exacting control in the Autoclave process results in uniformity from cycle to cycle.
- No efflorescence as limes and salts unite with silicates to form new structures free of leaching or efflorescence
Lighter means easier to work with
- Dried well below standard residual moisture content means less water resulting in a lighter block.
- Save 1,000 of lbs. in lifting and carrying our lighter block, as much as 4,000 lbs. on only 1,000 block.
Stronger then conventional block
- Complete curing, within 8 hours, at full strength, whereas other conventional blocks making process’s take 28 days to cure to full strength.
- Army Corps of Engineers recognize Autoclave as superior blocks above other processes.
Shrinkage is virtually non-existant
- Save money with less wall reinforcement, few joint controls
- Tests prove 50% less shrinkage than non-Autoclave process
- Less volume change even when they get wet
Avoid call backs
- Stronger, tougher block with less shrinkage and change in volume means, when installed properly, far less shifting and movement, resulting in mortar cracking virtually eliminated
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The Design
The first step in design is the size and shape of the block. There are a variety of shapes, however the basic block is 40cm long and 20cm high with 10cm, 15cm, 20cm, 25cm and 30cm widths. The second step in design is the material of which it is made.
There are two main categories:
Regular Concrete
Which is a mixture of Portland cement, silica flour, sand, gravel and
limestone screenings. (Limestone, sand and gravel aggregates)
Slag
Which is byproduct of steel and is lighter than concrete in fact it is
2/3 weight of regular concrete. No limestone is used. Although slightly
more expensive than concrete, it absorbs sound better and has greater
fire resistance than regular concrete
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The Process
There are five easy steps; Mixing, Moulding, Pre-Curing, Final Curing, Storage or Delivery
Mixing/Automated Batching
The cement, silica flour and aggregates are measured and mixed in the
prescribed amounts with water then fed down to moulding machines.
Moulding
The hopper feeds this mixture down to the block machines. It is then
formed and pressed under extreme pressure in the block moulds into what
is known as wet or green blocks. All cutting, e.g. scored blocks, or
forming is done at this time. These blocks are made on a steel pallet
which are then loaded onto steel racks to be moved into the Autoclave
for precuring.
Pre-Curing
This stage allows blocks to set properly as hydration occurs making
blocks stronger over a 2-3 hour period. This is done inside the plant in
an Autoclave which is pre-heated to a constant temperate with the
Autoclave door open, time and temperature are monitored to ensure proper
curing.
Curing
This stage takes place within an Autoclave, which is 33m long and 2.5m
in diameter. Here the blocks are put under intensive heat (177c) and
steam pressure (1000kpa) for approximately 4-6 hours. Upon removal from
the Autoclave, the blocks are cured and ready for installation.
Storage/Delivery
Following full curing the blocks are then removed and loaded onto a
pallet loading machine which evenly stacks the set amount of blocks and
then rolls each pallet on to an outdoor shipping area to be picked up by
forklift and placed in designated storage areas or placed on flatbed
trucks for delivery.
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